Evaluation Of Local Rock Stability On Dazu Rock Carving Niche Of Sakyamuni Entering Nirvana

As a model of late Chinese cave statue art,the Dazu Rock Carvings in Dazu District,Chongqing,contain rich historical,cultural,and artistic values.Among them,the Shakyamuni Buddha statue(also known as the Reclining Buddha),known as the world’s largest reclining bust,has been exposed to the natural environment for a long time,and inevitably under the combined effect of internal and external stresses damage.Over the centuries,weathering and spalling,fracture development,and collapse of the niche in the Reclining Buddha section have intensified,becoming a serious threat to the stability of the Reclining Buddha,which will lay a hidden danger to the long-term integrity of the Reclining Buddha.To better protect the reclining Buddha,this paper takes the case platform and the north and south pillars in the reclining Buddha section as the research object,based on the acquired 3D laser scanning information,and conducts an in-depth analysis of the high-precision problems in reconstructing the NURBS surface from the acquired massive point cloud,summarizes the methods to improve the accuracy of the inverse modeling model of stone cultural relics,and combines the results of on-site geological investigation and the existing state of the research object,and adds the internal and surface of the rock body on the basis of the surface model.Then the stability analysis was carried out by using FLAC3 D finite difference software to reveal the deformation law of the case platform and the north and south pillars.(1)The process of recovery of digital information and establishment of solid model takes point cloud information as the base and physical information as the reference,and uses Geomagic Studio,Rhino and other software to transform the point cloud information into solid model,which better combines the surface and internal information of the rock mass and has high reconstruction accuracy.(2)The north and south columns in the existing state,the surface repair material and the internal sandstone displacement basically show a strip-like distribution,and the visible displacement difference is obvious,the top of the niche is supported by the repair material,and the niche stability of the top of the inverted ladder platform is better.Based on the strength discount method,the damage gradually expands upward,and when Fs=2.8,the connection between the column and the column base,the cliff wall and the weak interlayer produce unstable through damage.(3)The case platform shows a displacement difference in the unloading fissure,and the trend of main stress connection is presented along the fissure end to the depression of the top surface of the supply platform,which leads to the intensification of the damage effect of the fissure.After the strength reduction,the stability of the surrounding rock body in the fissure section is weakened,and the penetration phenomenon appears to the inner side of the cliff wall and the depression of the connection between the desk elevation and the platform respectively,and the shear and oblique slip damage occurs respectively,and the slip surface is approximately sheared out from the lowermost weak interlayer,and the maximum calculated displacement is 0.6cm,and the current safety factor of the desk is 2.86.(4)Under the action of horizontal seismic load,the time course curves of the case platform and the north-south column model are basically the same,with the approximate "surface amplification" effect in the direction of the air surface and the "elevation effect" in the height direction.